Turbine systems are continuously being modified to increase efficiency and decrease cost. One method for increasing the efficiency of a turbine system includes increasing the operating temperature of the turbine system. To increase the temperature, the turbine system must be constructed of materials which can withstand such temperatures during continued use.
In addition to modifying component materials and coatings, one common method of increasing temperature capability of a turbine component includes the use of cooling features. For example, many turbine components include impingement sleeves or impingement plates positioned within an internal cavity thereof. The impingement sleeves or plates include a plurality of cooling channels that direct a cooling fluid towards an inner surface of the turbine component, providing impingement cooling of the turbine component. However, forming separate individual impingement sleeves for positioning within the turbine components increases manufacturing time and cost. Additionally, impingement sleeves typically generate significant cross flow between the impingement sleeve and the turbine component, and require sufficient cooling fluid to provide fluid flow through each of the cooling channels at one time, both of which decrease efficiency of the system.
Another method of cooling turbine components includes the use of serpentine cooling. Serpentine cooling includes passing a cooling fluid through a passage within the turbine component to simultaneously cool both the pressure and suction side walls of the component. The simultaneous cooling of both walls may overcool one wall in order to sufficiently cool the other. The overcooling of one wall leads to thermal gradients as well as unnecessary heat pick-up, both of which decrease downstream cooling effectiveness and cooling efficiency.